From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 24387 invoked by alias); 14 Jan 2007 21:34:31 -0000 Received: (qmail 24377 invoked by uid 22791); 14 Jan 2007 21:34:29 -0000 X-Spam-Check-By: sourceware.org Received: from 195.22.55.53.adsl.nextra.cz (HELO host0.dyn.jankratochvil.net) (195.22.55.53) by sourceware.org (qpsmtpd/0.31) with ESMTP; Sun, 14 Jan 2007 21:34:24 +0000 Received: from host0.dyn.jankratochvil.net (localhost [127.0.0.1]) by host0.dyn.jankratochvil.net (8.13.8/8.13.8) with ESMTP id l0ELYF04005250; Sun, 14 Jan 2007 22:34:15 +0100 Received: (from jkratoch@localhost) by host0.dyn.jankratochvil.net (8.13.8/8.13.8/Submit) id l0ELYECi005249; Sun, 14 Jan 2007 22:34:14 +0100 Date: Sun, 14 Jan 2007 21:34:00 -0000 From: Jan Kratochvil To: Daniel Jacobowitz Cc: gdb-patches@sourceware.org, brobecker@adacore.com Subject: Re: [PATCH] Fix PPC non-CFI + CFI unwinding (incomplete in HEAD) Message-ID: <20070114213414.GA5184@host0.dyn.jankratochvil.net> References: <20070113093052.GA27383@host0.dyn.jankratochvil.net> <20070113160420.GB28179@nevyn.them.org> <200701131631.l0DGVW3W029896@brahms.sibelius.xs4all.nl> <20070113164028.GA29436@nevyn.them.org> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="vGgW1X5XWziG23Ko" Content-Disposition: inline In-Reply-To: <20070113164028.GA29436@nevyn.them.org> User-Agent: Mutt/1.4.2.2i X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2007-01/txt/msg00345.txt.bz2 --vGgW1X5XWziG23Ko Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-length: 726 On Sat, 13 Jan 2007 17:40:28 +0100, Daniel Jacobowitz wrote: ... > I was thinking of this: > http://sourceware.org/ml/gdb-patches/2004-12/msg00249.html > http://sourceware.org/ml/gdb-patches/2005-06/msg00242.html > > I think someone needs to combine Joel's and Jan's patches. Joel's is > nicer in that it uses branch_dest and the right mask for blrl; Jan's > is nicer in that it checks whether lr was saved or is now lost. Attached for: http://sourceware.org/ml/gdb-patches/2004-12/msg00249.html and it does not handle in any way http://sourceware.org/ml/gdb-patches/2005-06/msg00242.html as it would be IMO more appropriate to base it on the called code content but "I do not have that Darwin code". Regards, Jan --vGgW1X5XWziG23Ko Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="gdb-ppc-combo.patch" Content-length: 2362 2007-01-14 Joel Brobecker Jan Kratochvil * rs6000-tdep.c (bl_to_blrl_insn_p): New function. (skip_prologue): Allow bl->blrl used by a PIC code. --- gdb/rs6000-tdep.c 9 Jan 2007 17:58:57 -0000 1.260 +++ gdb/rs6000-tdep.c 14 Jan 2007 21:24:51 -0000 @@ -902,6 +902,30 @@ store_param_on_stack_p (unsigned long op return 0; } +/* Assuming that INSN is a "bl" instruction located at PC, return + nonzero if the destination of the branch is a "blrl" instruction. + + This sequence is sometimes found in certain function prologues. + It allows the function to load the LR register with a value that + they can use to access PIC data using PC-relative offsets. */ + +static int +bl_to_blrl_insn_p (CORE_ADDR pc, int insn) +{ + const int opcode = 18; + const CORE_ADDR dest = branch_dest (opcode, insn, pc, -1); + int dest_insn; + + if (dest == -1) + return 0; /* Should never happen, but just return zero to be safe. */ + + dest_insn = read_memory_integer (dest, 4); + if ((dest_insn & 0xfc00ffff) == 0x4c000021) /* blrl */ + return 1; + + return 0; +} + static CORE_ADDR skip_prologue (CORE_ADDR pc, CORE_ADDR lim_pc, struct rs6000_framedata *fdata) { @@ -1133,18 +1157,19 @@ skip_prologue (CORE_ADDR pc, CORE_ADDR l to save fprs??? */ fdata->frameless = 0; - /* Don't skip over the subroutine call if it is not within - the first three instructions of the prologue and either - we have no line table information or the line info tells - us that the subroutine call is not part of the line - associated with the prologue. */ - if ((pc - orig_pc) > 8) - { - struct symtab_and_line prologue_sal = find_pc_line (orig_pc, 0); - struct symtab_and_line this_sal = find_pc_line (pc, 0); - if ((prologue_sal.line == 0) || (prologue_sal.line != this_sal.line)) - break; + if (bl_to_blrl_insn_p (pc, op)) + { + /* If we did not yet retrieved LR into some GPR + all our chances are lost. On the other hand already + stored LR is still kept intact in its GPR. */ + if (lr_reg == -1) + { + /* Invalidate lr_reg, but don't set it to -1. + That would mean that it had never been set. */ + lr_reg = -2; + } + continue; } op = read_memory_integer (pc + 4, 4); --vGgW1X5XWziG23Ko--